An optical frequency comb device includes: an optical waveguide; a first mirror disposed at a first position in the optical waveguide; a second mirror disposed at a second position different from the first position, in the optical waveguide; a gain medium and a saturable absorber which are disposed between the first mirror and the second mirror; and a controller that fixes one of a repetition frequency and a carrier-envelope offset frequency of an optical frequency comb output from an end of the optical waveguide, and changes the other of the repetition frequency and the carrier-envelope offset frequency.

A method for transmitting and receiving an electromagnetic radiation beam, adapted to determine an orbital angular momentum of the received electromagnetic radiation beam, is described. There is further described a system for transmitting and receiving an electromagnetic radiation beam, capable of performing the aforesaid method. A method for performing a telecommunication of signals modulated according to any modulation technique and grouped by means of orbital angular momentum multiplexing is further described. There is further described a telecommunication system capable of performing the aforesaid method for performing a telecommunication of modulated signals.

A method for demultiplexing and demodulating (in particular, “locally” demultiplexing and demodulating) amplitude-modulated signals grouped by means of orbital angular momentum multiplexing is described. The method involves demultiplexing and demodulating information a(t), b(t) modulated on each of a first modulated beam Fm1 and at least one second modulated beam Fm2, based on phase difference values ΔP.sub.ab and ΔR detected by beam detectors located downstream of an interferometric structure 40 to which two portions of the electromagnetic beam carrying the modulated channels are provided as inputs, multiplexed in the orbital angular momentum variable. There is also described a corresponding system 100 for demultiplexing and demodulating amplitude-modulated signals capable of implementing the aforesaid method.

A system may include a laser source configured to generate a first laser light beam, an atom trap, and a multi-channel acousto-optic modulator (AOM). The multi-channel AOM may include a beamsplitter to split the first laser light beam into a plurality of second laser light beams for the atom trap, a common acousto-optic medium configured to receive the plurality of second laser light beams, and a respective plurality of electrodes coupled to the common acousto-optic medium for each of the second laser light beams. The system may also include a plurality of radio frequency (RF) drivers each configured to generate respective RF drive signals for each of the plurality of electrodes.

An optical transmission apparatus includes a wavelength converter that wavelength-converts input signal light using a nonlinear optical medium to output the converted signal light, a memory that holds first information relating to a wavelength conversion characteristic of the wavelength converter, a communication interface that receives second information relating to a second wavelength conversion characteristic of an adjacent optical transmission apparatus, and a control circuit that determines, using the first information and the second information when the second information is received, an excitation light frequency at which a gain deviation of main signal light subjected to a wavelength conversion is minimized to set the determined excitation light frequency in the wavelength converter.

An optical transmission apparatus includes a wavelength converter that wavelength-converts input signal light using a nonlinear optical medium to output the converted signal light, a memory that holds first information relating to a wavelength conversion characteristic of the wavelength converter, a communication interface that receives second information relating to a second wavelength conversion characteristic of an adjacent optical transmission apparatus, and a control circuit that determines, using the first information and the second information when the second information is received, an excitation light frequency at which a gain deviation of main signal light subjected to a wavelength conversion is minimized to set the determined excitation light frequency in the wavelength converter.

A method for transmitting and receiving an electromagnetic radiation beam, adapted to determine an orbital angular momentum of the received electromagnetic radiation beam, is described. There is further described a system for transmitting and receiving an electromagnetic radiation beam, capable of performing the aforesaid method. A method for performing a telecommunication of signals modulated according to any modulation technique and grouped by means of orbital angular momentum multiplexing is further described. There is further described a telecommunication system capable of performing the aforesaid method for performing a telecommunication of modulated signals.

An optical transmission apparatus includes a wavelength converter that wavelength-converts input signal light using a nonlinear optical medium to output the converted signal light, a memory that holds first information relating to a wavelength conversion characteristic of the wavelength converter, a communication interface that receives second information relating to a second wavelength conversion characteristic of an adjacent optical transmission apparatus, and a control circuit that determines, using the first information and the second information when the second information is received, an excitation light frequency at which a gain deviation of main signal light subjected to a wavelength conversion is minimized to set the determined excitation light frequency in the wavelength converter.

An optical transmission apparatus includes a wavelength converter that wavelength-converts input signal light using a nonlinear optical medium to output the converted signal light, a memory that holds first information relating to a wavelength conversion characteristic of the wavelength converter, a communication interface that receives second information relating to a second wavelength conversion characteristic of an adjacent optical transmission apparatus, and a control circuit that determines, using the first information and the second information when the second information is received, an excitation light frequency at which a gain deviation of main signal light subjected to a wavelength conversion is minimized to set the determined excitation light frequency in the wavelength converter.

A system may include a laser source configured to generate a first laser light beam, an atom trap, and a multi-channel acousto-optic modulator (AOM). The multi-channel AOM may include a beamsplitter to split the first laser light beam into a plurality of second laser light beams for the atom trap, a common acousto-optic medium configured to receive the plurality of second laser light beams, and a respective plurality of electrodes coupled to the common acousto-optic medium for each of the second laser light beams. The system may also include a plurality of radio frequency (RF) drivers each configured to generate respective RF drive signals for each of the plurality of electrodes.